The present invention relates to a multiple image photographing apparatus in which a plurality of images displayed one at a time on an image displaying device such as a CRT (cathode-ray tube) are recorded on a single sheet of film. More particularly, the invention relates to a multiple image photographing apparatus employing a variable magnification system.
Recently, a multiple image photographing apparatus for photographing images displayed on a television monitor and recording such images on a sheet of film has been utilized for medical diagnostic purposes. An example of a multiple image photographing apparatus of this type is disclosed in Japanese Laid-Open Patent Application No. 60937/1980. The apparatus includes a television monitor having a display screen directed upwardly, a film conveying device disposed above the television monitor to move the film parallel to the display surface of the television monitor, and a photographing lens arranged between the film conveying device and the television monitor, with the television monitor being movable parallel to the film conveying plane.
This apparatus suffers from several drawbacks. First, photographing is carried out with the film held in a horizontal position. Therefore, the degree of flatness of the film is liable to be adversely affected due to the force of gravity, and accordingly, the developed image may be of unavoidably low quality. In addition, since exposure operations are carried out successively while the film is being moved in a horizontal plane, the area required for accommodating the apparatus is necessarily large.
In order to solve the above-described problems, the present applicant has proposed a multiple image photographing apparatus, which is described in U.S. patent application Ser. No. 477,461. The apparatus includes an image display device for displaying images to be photographed, a projecting optical system for focusing the image displayed on the picture displaying device on film, and a film conveying mechanism. A mirror is arranged in the projecting optical system, and the picture displaying device is movable horizontally while the film conveying mechanism moves the film vertically. This apparatus is advantageous in that the flatness of the film is not affected by by the force of gravity, and accordingly the quality of the developed images is improved. Moreover, the installation area of the apparatus is significantly reduced.
An object of the present invention is to improve the above-described conventional multiple image photographing apparatus. More specifically, an object of the invention is to provide a multiple image photographing apparatus in which, in addition to the above-described advantages, the magnification factor is made variable by adding a simple magnification varying mechanism to the above-described conventional multiple image photographing apparatus.
A conventional magnification varying mechanism will be briefly described. As an example, Japanese Laid-Open Patent Application No. 60971/1980 discloses a multiple image photographing apparatus in which, to vary the photographing magnification, the photographing lens is replaced and the optical path length is varied by moving the television monitor vertically. The conventional photographing lens is replaced with a lens board having lenses and shutters in a number equal to the number of images to be recorded on a single film sheet or frame. A suitable lens among the plural lenses is selected according to the desired magnification and the position of the image on the film.
However, this apparatus too involves certain drawbacks. First, since in a multiple image photographing operation using the above-described lens board images formed by different lenses are recorded on the same film sheet or frame, the photographing lenses must be strictly uniform, and accordingly the apparatus is considerably expensive. Secondly, in order to move the television monitor vertically, the necessary mechanism and its operation are intricate and the construction thereof must be rugged, and therefore the apparatus is necessarily expensive.